1. Field of the Invention
The present invention relates to the field of telecommunications. More particularly, the invention is concerned with converting a special handling number into a specially configured translation number that includes a destination output set of digits which are preferably the last four digits of the dialed number. This translation number is transported over the network from an originating switch to a terminating switch which then outputs the output set contained in the translation number to the destination.
2. Description of the Prior Art
Certain telephone numbers such as xe2x80x9c700xe2x80x9d, xe2x80x9c800xe2x80x9d and xe2x80x9c900xe2x80x9d numbers require special handling for both routing and billing. When a call is placed by dialing one of these special handling numbers, the originating switch of the telecommunications network requests a translation of the dialed number from a remote database. The database responds by providing a translation number corresponding to the dialed special number. The originating switch then uses the digits of the translation number as pointers in database tables for retrieving network routing instructions to the destination by way of a terminating switch. The translation number is also transported to the terminating switch.
When the terminating switch receives the translation number, it also uses this number to retrieve data from a set of databases that include instructions concerning special features requested by the customer. These include, for example, instructions concerning Dialed Number Identification Service (DNIS) whereby the customer specifies which digits should be outpulsed to the customer destination for identifying the dialed number. This is particularly useful when the customer has multiple 800 numbers terminating at the same destination. Some customers of 800 services are known as xe2x80x9cresellersxe2x80x9d who subscribe to large blocks of 800 numbers (sometimes as many as 10,000 wherein the reseller subscribes to an entire exchange represented by single NXX prefix) terminating at just one or a relatively few destinations and then resell the associated 800 services to individual customers. The reseller may have its own tandem switch at the destination to act as a gateway into a limited network of reseller.
As those skilled in the art will appreciate, the terminating switch must store in memory the required data for providing DNIS and other features for each 800 number terminating at that switch. When large blocks of 800 numbers terminate at a given switch, the normally available memory capacity of the switch can be exceeded. When this occurs, additional capacity must be added, which is expensive and can be disruptive to network operations.
The present invention solves the prior problems discussed above and provides a distinct advance in the state of the art. More particularly, the call handling system hereof substantially reduces the amount of memory required to handle large blocks of special calls terminating at a given destination.
In the preferred embodiment of the present invention, a translation number corresponding to special handling number is configured to include at least a portion of the output set of digits to be outpulsed to the destination from the terminating switch. The translation number is also configured and used for routing the call over the network from an originating switch to a terminating switch. In operation, the translation number is transported to the terminating switch which outpulses the output set contained in the translation number to the destination thereby eliminating the need for the terminating switch to store this output set in memory.
In preferred forms, all of the special numbers of a specified block of numbers are configured to include the same NXX prefix and the same NPA prefix. The terminating switch stores one or both of these prefixes in memory and then retrieves and adds this prefix information to the output set of digits in order to deliver a seven or ten digit number to the destination that matches the corresponding portion of the dialed number. In this way, only one prefix or prefix set need be stored in the memory of the terminating switch.